Lead alloy



Patented Feb. 3, 1931 UNITED [STATES PATENT OFFICE ROBERT JAY SHOEMAKER,OF CHICAGO, ILLINOIS, ASSIGNOR TO S. 8: T. METAL COM- PANY, OF CHICAGO,ILLINOIS, A CORPORATION OF ILLINOIS LEAD ALLOY No Drawing.

The invention relates to metal .compositions and its object is toprovide a composition suitable for cable coverings, pipes and otherarticles, consisting principally of lead but containing very smallquantities of lithium and small amounts of other metals, whereby thetendency of the lead to crystallize is largely overcome, and the lead ismade tougher, and to a certain extent harder, by the use of a hardeningagent or agents which will not corrode in moist atmospheres or dross outwhen the alloy is melted in casting for example.

Lithium used in relatively large quantities has been proposed as ahardening agent for lead. The disadvantage, however, of lead so hardenedis that it is particularly liable to corrosion and to drossing whenmelted due to the large amount of the hardening agent present. The costof such lead alloy is also very high since lithium is an expensivesubstance.

I have discovered that lead may be toughened, and hardened to someextent, and its tendency to crystallize very considerably reduced by theuse of extremely small amounts of lithium, the effect of this alloyingsubstance in producing a toughening effect on the lead being quitesurprising and out'of all proportion to the amounts used; and that thecost of the alloy may be reduced without detriment to its qualities 'byusing also as a hardening and toughening agent a certam amount ofcalcium and tin, in which case it appears to be necessary to introduceinto the composition a very small quantity of aluminum to prevent thecalcium from drosslng out.

The alloy sition:

Lithium 0.01% amount 0.02%.

Calcium 0.1% to 0.3%; preferable amount may have the following compoto0.03% preferable Application filed August 2, 1928. Serial No.

Tin 0.25% to 0.5%; preferable amount 0.

O. Aluminum 0.02% to 0.1%; preferable amount 0.5%.

Lead to make up 100%.

It will be understood that the above proportions are by weight.

The aluminum appears to have no function so far as the hardening ortoughening of the lead is concerned. Its value is in keeping the calciumfrom drossing out when the components are melted incompounding or Whenthe alloy itself is melted,

The compound is made as follows The lead is first melted to atemperature of approximately 1600 Fahrenheit under a protective coatingconsisting preferably of molten calcium chloride. The tin and aluminumare introduced into the melt through the calcium chloride coating,either as metallic elements or, preferably for convenience, astin-aluminum alloy. The calcium is then introduced in the same Way, itbeing desirable to introduce the calcium after the tin and aluminum inorder to prevent the calcium chloride from foaming. The melt is thenallowed to cool to a temperature of about 600 to 700 Fahrenheit, thecalcium chloride being in the meantime stripped ofi' after itsolidifies, which takes place at a temperature of approximately 1000Fahrenheit. Rosin is then introduced into the lead and the lithium mixedin While the rosin is burning.

he toughenss of the lead, and also its hardness in comparison with purelead are quite remarkable in view of the very small quantities ofalloying agents used. More; over the tendency of the lead to rystallizeis checked to a very large degree. The alloy is stable, provided catedare not exceeded, both as against corrosion in moist atmospheres and asagainst drossing when the metal is melted 1'. r casting, for example.

I claim:

1. A tough, slightly hardened, non-corrosible lead alloy consisting oflead and, by weight of the alloy, from 0.01% to 0.03%

5 lithium; from 0.1% to 0.3% calcium; from 0.25% to 0.5% tin; and from0.02% to 0.1% aluminum.

2. A tough, slightly hardened, non-corrosiblc lead alloy consisting oflead, and by 'weight, approximately 0.02% of lithium; 0.2% calcium; 0.3%tin; and 0.05% aluminum ROBERT JAY SHOEMAKER.

I claim:

1. A tough, slightly hardened, non-corrosible lead alloy consisting oflead and, by weight of the alloy, from 0.01% to 0.03%

5 lithium; from 0.1% to 0.3% calcium; from 0.25% to 0.5% tin; and from0.02% to 0.1% aluminum.

2. A tough, slightly hardened, non-corrosilole lead alloy consisting oflead, and by weight, approximately 0.02% of lithium;

w 0.2% calcium; 0.3% tin; and 0.05% aluminum ROBERT JAY SHOEMAKER.

CERTIFICATE OF CORRECTION.

Patent No. 1,791,148. Granted February 3, 1931, to

ROBERT JAY SHOEM AKER.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,line 49, for the decimal character "0.5%" read 0.05%; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Office.

Signed and sealed this 24th day of February, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,791,148. Granted February 3, 1931 ROBERT JAY SHOEMAKER.

printed specification of the above numbered patent Page 1, line 49, forthe decimal character "0.5%" read 0.05%; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 24th day of February, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

